The owner of a one-hundred-thousand dollar condominium unit asked if something could be done about the noise that the gentleman upstairs makes when he uses his toilet. He was referring to the sound of liquid hitting the toilet water in the bathroom of the unit directly above. This tinkling sound is carried along the plumbing pipes through walls and ceilings. The question was directed at a board of directors at a condominium association meeting. Everyone said that they were familiar with the irritating sound and all responded that absolutely nothing could be done about it.
A person who is extremely cognizant of this problem could observe the attempts of some toilet manufacturers to design a toilet bowl that acts as both a urinal and a seatable pot. Designs that try to offer the extra surface provided by a urinal fail to accomplish their objective. This is because the water level of the toilet bowl is not accurately controllable. In addition, as the shape of the toilet bowl becomes less hemispherical the flush becomes less effective.
The source of the noise is a falling column of liquid hitting the surface of standing water. The surface vibrates because the natural surface tension tries to keep the liquid water molecules together. If the flowing column of liquid was directed at a non-vibrating surface there would be no noise.
The common household bathroom toilet is a magnificent device which performs frequently and repeatedly without failure. It usually lasts longer than any other piece of equipment in the modern home. Past attempts to redesign the toilet bowl have not resulted in a resolution to the noise problem. The exact surface level of the standing water in the bowl is not constant and cannot be individually adjusted. Because of this, a definite unsubmerged non-liquid surface area of the inner bowl cannot be assured. This is the primary reason that toilet designers have been unable to guarantee a non-liquid surface.
There are two reasonable ways to avoid the noise of urine splashing into the bowl of water. One is to install a commercial, public, type urinal in every bathroom. Everyone knows that these devices offer surfaces that don't vibrate sound waves when hit with a flowing column of liquid. The second solution would be the act of the gentleman sitting down on the toilet seat. This reduces the gravitational acceleration which adds energy to the liquid stream and suppresses the modular build up of the falling droplets. The first solution would require the size of the bathroom to be increased by more than twice that of normal space allotments. The second solution fails because of habit and convenience. Since it is natural and comfortable for gentlemen to remain standing, it must be expected that men will not sit. Thus the common home toilet must also serve as a urinal.